arXiv subjects

S. Wippermann

Publications and source records attributed to S. Wippermann.

3 recordsLinked to original sources

arXiv2022

Dielectric properties of nanoconfined water from ab initio thermopotentiostat molecular dynamics

We discuss how to include our recently proposed thermopotentiostat technique [Phys. Rev. Lett. 126, 136803 (2021)] into any existing ab initio molecular dynamics (AIMD) package. Using thermopotentiostat AIMD simulations in the canonical NVT{\Phi} ensemble at constant electrode potential, we compute the polarization bound charge and dielectric response of interfacial water from first principles.

cond-mat.mtrl-sci↗

arXiv2020

Dielectric properties of nano-confined water: a canonical thermopotentiostat approach

We introduce a novel approach to sample the canonical ensemble at constant temperature and applied electric potential. Our approach can be straightforwardly implemented into any density-functional theory code. Using thermopotentiostat molecular dynamics simulations allows us to compute the dielectric constant of nano-confined water without any assumptions for the dielectric volume. Compared to the commonly used approach of calculating dielectric properties from polarization fluctuations, our thermopotentiostat technique reduces the required computational time by two orders of magnitude.

cond-mat.mtrl-sci↗

arXiv2014

Impurity-mediated early condensation of an atomic layer electronic crystal

While impurity has been known widely to affect phase transitions, the atomistic mechanisms have rarely been disclosed. We directly show in atomic scale how impurity atoms induces the condensation of a representative electronic phase, charge density wave (CDW), with scanning tunneling microscopy. Oxygen impurity atoms on the self-assembled metallic atomic wire array on a silicon crystal condense CDW locally even above the transition temperature, More interestingly, the CDW along the wires is induced not by a single atomic impurity but by the cooperation of multiple impurities. First principles calculations disclose the mechanism of the cooperation as the coherent superposition of the local lattice strain induced by impurities, stressing the coupled electronic and lattice degrees of freedom for CDW. This newly discovered mechanism can widely be applied to various important electronic orders coupled to lattice, opening the possibility of the atomic scale strain engineering.

cond-mat.mes-hall↗